1. Field of the Invention
The invention relates to window treatments and in particular to vertical Louvre Blinds each and travellers therefor.
2. Related Art
Vertical louvre blinds usually comprise a headrail with several travellers movable along the headrail by one means or another. Each of the travellers has a rotatable hook which holds a vane carrier. The vane carriers in turn hold the vanes or louvres of the blind. The travellers are capable of moving longitudinally along the headrail and imparting rotary movement to the hooks to rotate or tilt the louvres. The rotation is such that all of the louvres are operated simultaneously so that they always extend in planes substantially parallel to one another. Provision is often made to allow the blinds to move slightly if they are inadvertently hit.
The travellers are pulled through the headrail by a cord attached to a bridle on which the lead traveller is mounted. As the bridle and lead traveller are pulled along the headrail slack is taken up in a spacer means between the lead and second traveller. The spacer means pulls adjacent travellers along at predetermined separations. This provides even spacing between the travellers when extended. When the cord is pulled in the opposite direction the lead traveller moves back towards its adjacent traveller providing slack in the separation means. The lead traveller collides with the second traveller and pushes it along. These travellers continue along to stack each adjacent traveller and pushing all the travellers back to the retracted position.
With center draw types of headrail where two blinds are mounted for movement towards and away from each other, it is necessary to provide two bridles for two lead travellers. With such a construction, the pull cords for the blind have their ends attached to one of the bridles and are attached to the other bridle intermediate the ends of the cord. With prior constructions this connection intermediate the ends of the pull cord has typically involved the use of a traveller support which is made of stamped metal with stamped protrusions for connecting to the cord, as for example, described in U.S. Pat. No. 3,427,679 and Canadian Patent No. 740,252. Such stamped supports present sharp edges which can wear on the cord. Also the stamped metal protrusions can loosen during long time use of the blind. The prior art also includes blind constructions wherein master carriers for the blind are manufactured from thermoplastic material with the cord end held therein by a tight non-slipping frictional fit. See, for example, U.S. Pat. No. 4,438,798.
Further, some blind arrangements result in unequal amounts of blind material on either side of the meeting point of the two blinds as they are drawn together. The prior art constructions are provided with mechanisms to permit continued movement of the larger section after the smaller section of blind has been fully extended or fully retracted. This is necessary in order to fully open or fully close the larger section of blind. In this regard reference is made to U.S. Pat. Nos. 4,293,021, 4,552,195 and 4,648,436 which disclose various forms of cord connections permitting slippage when the blind reaches a fully extended or retracted position.